The best replacement for leek is onion.

The best alternatives to leek are rated as following:
★★★★★  onion
★★★★  green onion
★★★★  leak
★★★  scallion
★★  shallot
★  spring onion
★  chive
★  blur
  cryo
  daffodil
  fennel
  negi
  bok choy
  delica
  skyline

Your alternative for leek is not listed? Suggest!
Speaking about leek, one probably shouldn't forget about tau kwa.

Other search terms related to leek and their ratings are:
★★★★★ tau kwa
★★★★ chinese sausage
You have in mind a companion for leek and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of leek in all years. Click on graph for more.
leek
onion
green onion